As a high-performance permanent magnet, there have been known rare-earth magnets such as a Sm—Co based magnet and a Nd—Fe—B based magnet. When a permanent magnet is used for a motor of a hybrid electric vehicle (BEV) or an electric vehicle (EV), the permanent magnet is required to have heat resistance. In a motor for HEY or EV, a permanent magnet whose heat resistance is increased by replacing a part of neodymium (Nd) of Nd—Fe—B based magnet with dysprosium (Dy) is used. Dy is one of rare elements, and thus a permanent magnet not using Dy is demanded. The Sm—Co based magnet has a high Curie temperature, and thus is known to exhibit excellent heat resistance as a magnet having a compositional system not using Dy.
In a motor or the like using the Sm—Co based magnet, the magnet is expected to realize favorable operating characteristics at a high temperature. However, a magnetization of the Sm—Co based magnet is lower than that of the Nd—Fe—B based magnet, and a sufficient value of maximum energy product ((BH)max) is not realized. In order to increase the magnetization of the Sm—Co based magnet, it is effective to replace a part of Co with Fe, and to increase an Fe concentration. However, a coercive force of the Sm—Co based magnet tends to decrease in a composition region having a high Fe concentration, and in addition to that, a squareness of hysteresis loop also tends to deteriorate. Accordingly, there has been demanded a technique of enhancing the coercive force and a squareness ratio of the Sm—Co based magnet having the high Fe concentration, while maintaining a high magnetization in the magnet.